The present invention relates to an electric plug connection arrangement, especially to an arrangement where a plug connection is to be used for medical/electrical purposes according to DIN 42802. The plug connector provides contact-protected or shock-proof connection of cables, for example for conductors extending from a patient to medical/electrical apparatus.
Connection arrangements of this type are already known. One drawback of the known arrangements resides in that occasionally plug elements and plug-holding fixtures of different configurations must be brought into use, depending on whether the connection is to be made with shielded or unshielded cables. With arrangements having shielded leads or conductors, special plug connections are provided in turn for the formation of the contact of signal conductor and shielding.
Objects of the present invention are to provide a simply constructed plug connection arrangement which is characterized by limited space requirements and is suitable for the connection of plug elements with either shielded or unshielded cables.
The foregoing objects are basically obtained by an electrical connector, comprising at least one plug element that is connectable to a cable and has a plug electrical contact member and a tubular insulating body surrounding and extending coaxially relative to the plug contact member. The insulating body is open at one end thereof to provide access to the plug contact member. A connection housing includes at least one plug-holding fixture for receiving the plug element. The plug-holding fixture has a housing contact member matable with the plug contact member and extendable through the open end of the insulating body. Electrical shielding is coupled to the connection housing. The electrical shielding has a flexible shield contact spring extending into the plug-holding fixture. The shield contact spring has an end part pre-biased to contact the housing contact member. A groove extends in an exterior surface of the insulating body parallel to a longitudinal axis thereof. The groove has a width adapted to a breath of the shield contact spring to receive the end part as the end part is disconnected from the housing contact member upon insertion of the plug element into the plug-holding fixture.
A coaxial connection arrangement is thus provided by which the same plug-holding fixture can be used regardless of whether the plug element to be inserted is coupled to a shielded or an unshielded cable. The shield-contact spring is pre-biased against the contact member in the plug-holding fixture, is raised upon insertion of the plug element, and is received and held in the longitudinal groove of the insulating body of the plug element. An additional advantage of the arrangement according to the present invention resides in that, before the insertion of the plug element, in other words when the plug-holding fixture is not in use, the housing contact member is short-circuited by means of the contact spring.
When plug elements with shielded cables are involved, since the groove extends longitudinally in the insulating body of the plug element, a shield contact of the shielding of the cable is accessible. Plug element insertion in the plug-holding fixture causes formation of the contact with the shield-contact spring of the plug-holding fixture. Thus, when the connection is produced for the signal conduction, the electrical connection of the shielding occurs simultaneously.
The arrangement according to the present invention is in full compliance with the standard regulations in effect for such arrangements. In the case of the plug element, a contact member can be provided according to DIN 42802, which cooperates in the plug-holding fixture with a complementary contact member in the form of a metal pin. The short-circuiting shield-contact spring is raised upon insertion of the plug element.
The tubular insulating body of the plug element can have a metal tube, on an interior insulating tube, which metal tube is coupled to the shield of the cable. The metal tube can be surrounded by an exterior insulating tube, which covers the metal tube and includes the shield contact in a contact-proof and shock-proof manner. The access of the shield-contact spring of the plug-holding fixture to the shield contact of the plug element occurs through a longitudinal groove or slot in the exterior insulating tube. With insertion of the plug element in the plug-holding fixture, the shield-contact spring is guided into this slot, and thus, produces the electrical connection of the shielding. The width of the longitudinal slot, and correspondingly the breadth of the contact spring, are selected to be sufficiently narrow that a testing tool corresponding to DIN IEC 601 cannot contact the metal tube. Thus the metal tube forming the shield contact is construed as non-contactable.
A catch projection can be provided in the slot of the exterior insulating tube of the plug element. In corporation with the contact spring of the plug-holding fixture, the catch projection forms a releasable catching device for the inserted plug element. Thus, a special advantage is obtained that the force for detaching the plug connection can be adjusted independent of the contact force by selection of the holding effect of the catch device in any desired, suitable manner.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, disclose a preferred embodiment of the present invention.